Petenia splendida

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Petenia splendida
Xanthistic red morph

Xanthistic red morph

Systematics
Order : Cichliformes
Family : Cichlids (Cichlidae)
Subfamily : Cichlinae
Tribe : Heroini
Genre : Petenia
Type : Petenia splendida
Scientific name of the  genus
Petenia
Günther , 1862
Scientific name of the  species
Petenia splendida
Günther , 1862

Petenia splendida is a cichlid from Central America that can reach a total length of up to half a meter (weight up to three kilograms; females stay a little smaller). He is in the New World subfamily Cichlinae ( Tribus Heroini ). Until a few years ago it was onlyof interestto the local population (even among the Maya ) as a good food fish (in Mexico and Guatemala this Cichlidae is called "Tenguajaqua" or "Tenguayaca"). In the English-speaking world, it bears the name "Bay Snook" ("snook" means "long nose") in allusion to its head shape. The German name "Fleckter Raubbuntbarsch" is completely uncharacteristic, even misleading, for this ambulance hunter . The genus Petenia is monotypical .

features

The elongated and laterally strongly flattened body is typical of the species. The basic color is shiny silvery (Latin splendidus "shiny") with a series of dark spots of various sizes along the sides of the body and irregularly scattered smaller ones on scales and fins. Some spots can have a light border, the eye spots on the caudal fin base (one on each side of the body) always are. The gill covers usually also have a round spot at eye level. The up to six larger flank patches expand into vertical bandages depending on the mood. The natural occurrence of a xanthistic color morph has been known since 1935 , which does not show any drawing features but a relatively uniform, reddish basic color.

The unpaired fins often show a yellowish or reddish tone. The caudal fin is rounded, its rear edge sometimes truncated at an angle so that the dorsal part is larger than the ventral part.

Fin formula : D XV / 13–16, AV – VII / 8–11, P 15, C 17. approx. 42 scales along the lateral line. Scaled cheeks. (2n =) 48 chromosomes.

The mouth is big; the gap in the mouth extends below the eye. When the fish opens its mouth, however, it becomes "huge" and tubularly stretched out. From the lurking position, it is pushed over the prey, mainly smaller fish, in a flash-like forward movement in a matter of seconds. If the prey is larger and cannot be fully brought into the tube, it is held in place by distinctly elongated upper jaw teeth.

Similar to the epibulus insidiator , the extension of the premaxillary that slides on the top of the skull is very long. When the mouth is closed, it extends almost to the occipital ridge. But the lower jaw itself is also pushed forward because the jockstrap is very flexible thanks to the soft, thin areas of cartilage. The advancement is done by lifting the skull and lowering the hyoid with a dead center overcoming. The Branchiostegalmembran (with mostly five radii) is of small size. The everted, thin-skinned mouth pipe measures 60 percent of the length of the head; their diameter at the tip is about 40 percent and thus exceeds the width of the fish's body. The genus Caquetaia with three South American species shows a similar mechanism, only slightly less pronounced . The labyrinth fish Luciocephalus pulcher catches its prey in a very similar way . A “trunk” folded in this way cannot be stretched completely straight.

The main food of the highly specialized Petenia splendida is fish and crustaceans . But it can also pick up other food animals from and from the ground, for which it has single-pointed, enlarged and curved "dog teeth". The gill trap consists of only a few short and wide appendages on the four elements of the first gill arch - an indication that the jockstrap and gill cover are not spread apart. The mouth is often stretched out even without food intake: when yawning to impress inwardly and when tugging the mouth very cautiously as part of the commentary behavior .

behavior

The fish, an eye-catcher thanks to its mouth pipe, is praised by aquarists for its peacefulness and tolerance. Although it occurs in open water (over mud, gravel and gravel; it does not need vegetation to hide or spawn, but likes to use it to lurk), it can withstand even in smaller tanks and can even get used to artificial food. Sometimes he lives alone, but more often in pairs or in smaller (or larger) groups. Sexual maturity occurs with a length of about 15 cm. Couples ready to spawn (who are said to be able to stay together for life) show an inconspicuous courtship with mutual fanning. The spawn (a few hundred eggs with a longitudinal diameter of 1.8 mm) is simply deposited on blocks or trunks that have been cleaned a little beforehand and guarded together ( substrate spawners ). The larvae hatch after about 72 hours and swim free after another 96 hours.

distribution

In larger rivers (e.g. Rio Usumacinta ) and lakes of the eastern capping, i. H. towards the Atlantic Ocean, northern Central America: in parts of Chiapas , in Quintana Roo , Tabasco and Yucatan (Mexico), Guatemala (it was described from the Peten ) and Belize - there mostly from hard water, at pH 6.8 to 7, 8th; Water temperature 26–28 ° C. After flooding, for example, it also occurs in smaller stagnant waters, even near the coast and there also in brackish cenotes . Petenia splendida was often released for human consumption or propagated in fish cultures. As a result, the original distribution can no longer be shown exactly.

As part of the global “tilapia projects” of the WHO , in addition to the large cichlid species Parachromis managuensis , which is also native to Central America , the blue tilapia Oreochromis aureus , which comes from North Africa and the Middle East , was exposed in Central America . Due to their enormous adaptability, the tilapia spread very successfully and displace ancestral species, including Petenia splendida .

literature

  • PC Wainwright, LA Ferry-Graham, TB Waltzek, AM Carroll, CD Hulsey and JR Grubich: Evaluating the use of ram and suction during prey capture by cichlid fishes. In: J. Exp. Biol. 204: 3039-3051 (2001)
  • TB Waltzek, PC Wainwright: Functional morphology of extreme jaw protrusion in neotropical cichlids . In: Journal of Morphology 257, 2003; Pp. 96-106.
  • JL Cochran: Diet, habitat and ecomorphology of cichlids in the Upper Bladen River, Belize. Diss. Texas A&M University 2008.
  • O. Rican, R. Zardoya, and I. Doadrio: Phylogenetic relationships of Middle American cichlids (Cichlidae, Heroini) based on combined evidence from nuclear genes etc. In: Molecular Phylogenetics and Evolution 49, 2008; Pp. 941-957.

Individual evidence

  1. ↑ a b c Stawikowski, R. & U. Werner (1998): The American cichlids . Vol. 1: 378-381. ISBN 3-8001-7270-4
  2. ↑ Xanthophore pigmentation, a consequence of melanin deficiency , occurs frequently in the very plastic heroine cichlids of Central America and is also documented for Vieja fenestrata , Amphilophus labiatus and Amphilophus citrinellus : CL Hubbs (1935): Freshwater fishes collected in British Honduras and Guatemala . Misc. Publ. Univ. Me. Mus. Zool. 28: 1-22
  3. ↑ Nourissat, J.-C. (1992): Au royaume des Petenia . Revue fr. Cichlidophiles 121 (9): 6-18
  4. ↑ Szymanski, K (1996): The Cenote-Azul from Bacalar . D. Aqu. u. Terr. Z. (DATZ) 49: 649-651
  5. ↑ Noiset, J.-L. & SA Hernandez (1991): Valorisation des marais par le développement de la pêche dans la région de San Pedro (Tabasco, Mexique) . Ass. Dével. Rech. Agr. Int. Louvain-la-Neuve

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